The present invention relates to systems for error proofing in order picking operations, inventory control systems and, more particularly, to controlling the completeness and optionally the sequence of selection or placement of items on a repetitive basis.
Particularly in the consumer goods market, but also in other areas of commerce, it is common for a manufacturer to be required to package and ship groups of parts for use in the subsequent assembly of an article by the consumer. For example, large toys and bicycles are often sold partially assembled and are packaged with the appropriate number and kind of fasteners and parts to allow complete assembly by the purchaser. If, however, the wrong types or numbers of fasteners and smaller parts are supplied or some parts are missing, the purchaser is delayed in his or her assembly and must either return the purchased article or request that the additional parts be supplied. This incomplete or erroneous packaging thus causes loss of consumer satisfaction with the purchase and ultimately loss of confidence in the ability of the manufacturer to supply a complete package for assembly.
Similarly, in the assembly of products by a manufacturer, a certain number and variety of component parts must be selected A particular product can be improperly assembled if this number and variety of parts are improperly or erroneously packaged.
In the past, the difficulty for the manufacturer has been the human error in the manual repetitive selection of items to form the desired group of items. In such a selection process it is common to provide a plurality of bins or shelves or other locations each of which holds a plurality of one of the parts to be selected. These may be adjacent one another so as to allow the worker or workers to select the desired parts or items to form the desired group. On the other hand, the bins, shelves or the like from which workers must select parts for a single assembly operation may be remote from each other within a manufacturing plant. In either case, no matter how careful the workers are, it is common to have an occasional error in the selection process and the number of errors depends on the skill and care of each worker. Therefore, it is usually necessary to constantly check the groups selected by the workers to ensure that the selection process is being carried out correctly and completely. The quality control process usually involves the random checking of selected groups of items to see if they are complete. However, even this checking results in some missed groups of improperly selected items which eventually get to the consumer.
In addition to random checking, it is known to provide a system for the repetitive selection of items where means are provided for sensing when each item of a desired group of items has been selected and whether the complete group of items has been selected in the proper sequence. This eliminates any error in the selection of items for the particular group of items intended to be selected. However, this system is "hard wired" and is designed for a specific selection sequence. Therefore, it is necessary to rewire or build a completely new system if the selection sequence is changed in any way. Thus, such a system is inconvenient to adapt to multiple uses and must be built for a specific group of items to be selected.
In loading storage racks and the like with inventory it is important that the proper components be loaded into the proper rack and that the proper number of components be so loaded. For inventory tracking and security purposes it is also important to monitor the number of components.
There are also operations in which it is important to ensure that all items used in a particular process are returned to a storage place therefor after the process is completed. For example, if a certain number of surgical instruments or gauzes are used in a surgical operation, it is important to ensure that all such instruments or gauzes are returned to a storage location after the operation is complete, or at least before a patient is closed. Without proper inventory control procedures there is a risk that one or more of the instruments used in the operation has been left inside the patient.
Morgan et al. U.S. Pat. No. 5,414,634, Hikosaka et al. U.S. Pat. No. 5,201,429, Kenik et al. U.S. Pat. No. 4,821,197, and Drapeau U.S. Pat. No. 3,908,800 each disclose an error proofing device or inventory control mechanism utilizing a rigid frame structure physically defining several openings which correspond to sources of items to be selected. Limitations of these devices are that the size and position of the respective openings are not adjustable and that they are not readily adaptable for use in connection with a variety of existing storage rack system.